Dale, who suffers from anxiety disorder, transferred to the specific purpose Campbell House School from the local mainstream school two years ago, and says the opportunities now open to him are "just breathtaking".

"I've never left this area because of my anxiety but I knew that if I didn't travel I wouldn't leave at all, and I didn't want to live my life that way," Dale said.

"I didn't know how to go about it and this is a good step for me."

This is the second such trip to be funded by Australian businessman Aviv Palti, who founded the Cambodia Rural School Trust to sponsor some of the poorest children in Siem Reap's rural communities to go to school and university.

When Mr Palti met Campbell House principal Marisa Pjanic at a yoga retreat in Thailand in 2013, they bonded over their work in helping break cycles of disadvantage.

"We'd been speaking for maybe five minutes and he said, 'I'd like to offer the opportunity for your school to bring along staff and students to Cambodia to do some volunteering'," said Ms Pjanic, who led the first trip in 2014.

Mr Palti covers the cost of flights and accommodation for five students and five staff from Campbell House, who spend 11 days during the July school holidays teaching Cambodian children English and talking about Australian and Aboriginal cultures. They also spend a day rebuilding a house and do some sightseeing at Angkor Wat.

Ms Pjanic said the experience is eye-opening for students at a school like hers.

"One of the things they gain is a sense of really valuing their education," she said.

"This is really the end of the line for some of our kids. They've been homeless and had all sorts of difficulties, and this is kind of their last opportunity to get some skills under their belt.

"This trip is a chance to see the world through different eyes and to share stories with young people from a very different culture to their own, and understand how they have so much advantage in Australian."

Mr Pjanic said it's especially moving to see how the experience affects the students.

"On our last trip, one of the students stopped eating one day," she said.

"I noticed he didn't have breakfast or lunch, and we sat down to dinner and I saw that he wasn't going to eat.

"I said, 'What's wrong?' and he said, 'I don't see why I deserve to eat when these kids have got nothing'.

"He was one of our poorest kids but it was really impacting for him to see real poverty, to stand on a dirt floor and see a house that was really just some sticks knocked together with no running water, just a bucket to collect whatever water fell into it."

For Alex Williams, 15, learning about Aboriginal culture so that he can teach others has been a highlight of preparing for the trip.

"My teacher and I are going to teach the kids how to write a story with Aboriginal symbols," Alex said.

"I've been learning what the symbols for man and woman are, and I was really surprised to learn that they don't have a symbol for spear."

Alex says he is hoping the trip will help him understand more about the lives of children in Third World countries.

"I want to learn about the way they go about their day. I reckon it'd be really good to see the way the kids live compared to us," he said.

"I take being spoilt for granted and if I go over there, I think I'll appreciate it more.

"And they said we were going to build a house, which is something I've wanted to do since I was a kid. That way I can give something in return."